Radiative transfer on the fly (astronomy and astrophysics): Building a radiation transfer algorithm that works in tandem with numerical hydrodynamics codes

Radiation plays a critical role, both in conveying information to us from the clouds that form stars and planets, and in transporting energy within these clouds. This project will build a radiation transfer algorithm that works in tandem with numerical hydrodynamics codes (in the first instance Smoothed Particle Hydrodynamics, but then also Adaptive Mesh Refinement and Moving Mesh codes) { as opposed to post-processing individual frames from a simulation. It will handle both (i) the radiation that regulates the temperature and chemical composition of the gas, and (ii) the radiation that determines the external appearance in line and continuum
radiation. (i) will allow us to perform much more realistic simulations of star and planet formation, that capture properly the interplay of hydrodynamics and thermodynamics, and the role played by thermodynamics in setting the characteristic scales of star formation, for
example the apparent minimum surface-density for star formation, or the putative universal diameter of filaments, and the characteristic mass of a star or prestellar core. The critical elements of the code will be (a) an adaptive tessalation algorithm that concentrates resolution where it is needed, and (b) a reverse ray-tracing scheme, which greatly reduces the memory and processing requirements, so that the code is very efficient. The code will then be used to perform simulations of star formation, to produce synthetic observations of the simulations, and to compare them with observations, both atomic and molecular line observations, and dust and free-free continuum observations, including the exquisite Herschel images that we are now producing using the PPMAP analysis tool (Marsh, Whitworth & Lomax, 2015, mnras 454 4282), which deliver approximately ten times finer spatial resolution than the standard analysis procedure, much more accurate column-densities, and detailed information on the distribution of dust temperature (as opposed to a single mean temperature). The student will become expert in radiation transport, numerical hydrodynamics, and the microphysics of star forming gas. This project will involve collaboration with astronomers in Prague.